diff --git a/src/geometry/polywarp.test.ts b/src/geometry/polywarp.test.ts
index 7f88b22..ccab70a 100644
--- a/src/geometry/polywarp.test.ts
+++ b/src/geometry/polywarp.test.ts
@@ -45,7 +45,8 @@ describe('polywarp', () => {
     const test: Vec2[] = [[488, 244], [1464, 732], [1952, 488], [976, 976]];
     const polyMax = Math.max(...test.map((m) => dist(applyPolyWarp(w, m), trueMap(m))));
     const homoMax = Math.max(...test.map((m) => dist(applyHomography(H, m), trueMap(m))));
-    expect(polyMax).toBeLessThan(homoMax * 0.05);
+    expect(homoMax).toBeGreaterThan(1e-3); // homography genuinely fails on barrel data
+    expect(polyMax).toBeLessThan(1e-6); // degree-3 fit of cubic data is near-exact everywhere
   });
 
   it('inverse round-trips machine points within a small tolerance', () => {